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Need help with building a custom pneumatic press

razoredgeknives

Plastic
Joined
Sep 6, 2019
Looking to build something like in the video below (11:08) but with dual pistons if possible (is that possible to do and have them sync up?)

Want to build this for dual purpose... For pressing Kydex sheaths or using with 1" thick aluminum slabs for quench plates when heat treating blades.

I'm thinking 1/2 ton for pressure but would be nice to have it variable... Not sure if it's best to incorporate air into this design or just make it electric?

I need it to press and hold for a few minutes.

Thoughts?

11:08 in video

YouTube
 
I would begin by assessing what you have in the shop work with. If ya have plenty of air good, just remember air one expensive commodity in the shop. Simple would be an apparatus like in the vid, just sit a bottle jack in the middle of the basal platen.
 
Looking to build something like in the video below (11:08) but with dual pistons if possible (is that possible to do and have them sync up?)

Want to build this for dual purpose... For pressing Kydex sheaths or using with 1" thick aluminum slabs for quench plates when heat treating blades.

I'm thinking 1/2 ton for pressure but would be nice to have it variable... Not sure if it's best to incorporate air into this design or just make it electric?

I need it to press and hold for a few minutes.

Thoughts?

11:08 in video

YouTube

pneumatic work great or you can always electric hydraulic. Units can be had cheap on ebay and the cylinders are also fairly cheap used.
 
My two cents. Dual pneumatic cylinders would be problematic, hard to keep together and regardless of the guide rods would inherently try to bind. A simple 4" cylinder at 120 psi gives you 1500 pounds of squish and that would be adjustable (down) with air regulation.

It would be a fun and simple build in my book.

Stuart
 
I built one some yrs back with two cylinders they never extended the same but once the first cylinder
reached resistance the second would catch up and equalize.
the only issue was speed I could not regulate speed without compromising force ,that is without a lot of solenoids and valving
It did what I need no problem
not too overly complex
 
That's a trivial thing to build and would work fine. Hell, I've got everything laying around the shop from old jobs. A 100mm bore cylinder would give you right at 1/2 ton. I'd go with 125mm bore (giving you about 7/8 of a ton) and use a pressure regulator to control the force. Unless you plan to automate it I'd use a simple hand operated pneumatic valve like a Festo VHER. Flow controls to control the speed and you're done.
 
I would begin by assessing what you have in the shop work with. If ya have plenty of air good, just remember air one expensive commodity in the shop. Simple would be an apparatus like in the vid, just sit a bottle jack in the middle of the basal platen.

yeah I've got a 7.5hp Eason compressor, it should be plenty of air. although I do have a regular right out of the compressor setting air to 100psi, I can certainly up that to like 130-150 if needed.

pneumatic work great or you can always electric hydraulic. Units can be had cheap on ebay and the cylinders are also fairly cheap used.

the electric hydraulic (from looking on ebay) look like a lot more pressure than I will need... they are massive lol. I just need like a 1 ton or something similar

My two cents. Dual pneumatic cylinders would be problematic, hard to keep together and regardless of the guide rods would inherently try to bind. A simple 4" cylinder at 120 psi gives you 1500 pounds of squish and that would be adjustable (down) with air regulation.

It would be a fun and simple build in my book.

Stuart

Yeah maybe I'm overbuilding. I want to use it for quench plates w/ 1" thick aluminum plate on each side (top and bottom) and just didn't want higher pressure in the middle of the plate vs. the sides.

I saw this on Alibiba, about $800. may be about what I need but not sure.

HTB1Nn8wh_nI8KJjSszbq6z4KFXaY.jpg


I built one some yrs back with two cylinders they never extended the same but once the first cylinder
reached resistance the second would catch up and equalize.
the only issue was speed I could not regulate speed without compromising force ,that is without a lot of solenoids and valving
It did what I need no problem
not too overly complex

Makes sense... yeah I don't want it to slam down on to the blades. Not sure what to do here.

That's a trivial thing to build and would work fine. Hell, I've got everything laying around the shop from old jobs. A 100mm bore cylinder would give you right at 1/2 ton. I'd go with 125mm bore (giving you about 7/8 of a ton) and use a pressure regulator to control the force. Unless you plan to automate it I'd use a simple hand operated pneumatic valve like a Festo VHER. Flow controls to control the speed and you're done.

Oh man thanks for your help! Yeah I may keep it single cylinder. Now I need to comprise a list of what to get. What do you think about these items?
- air cylinder: this looks like the largest they have of this type
- regulator
- it looks like the Vher levers don't have 3/8 npt which is what the two above units use... should I convert to 3/8 or look for something else?

The way it's set up in the video is with a regulator, a two way switch for up/down and then a pair of actuator buttons in series so you have to use both hands to actuate it according to the knife maker in that video. I don't have to set up mine exactly like it but just trying to figure out what to do. I'm pretty new to building stuff like this.
 
A bit confused here..a different member name replied, are you using two screen names?

In regards to the press pictured through Alibaba, I would run screaming from that, pneumatics are not a exact science and those cylinder will not extend or retract in perfect time. The skinny little guide bars with take a dump in a heartbeat when things go sour, plus if you don't load both side of the press identically the cylinders will try to cant/tilt the press plate and again, things go sour. The picture looks cool but the engineering is..'fake news'!:eek:

Stuart
 
Why don't you just copy Aaron's press? If you're concerned that the plates will deflect, make them thicker.
 
As the others have said I think a single cylinder with a larger diameter would be much easier and work better! My press generates less than 500# if I remember correctly so anything north of this should work fine for you! I don't think you'll need much pressure for the quench plates, and you definitely don't need a whole lot for thermoforming kydex as it's pretty pliable when it's hot. Too much pressure and you'll just crush the life out of your foam and reduce it's lifespan.

Also one tip: normal neoprene foams that are commonly used in kydex presses don't work so will in this application, because of the high clamp force it tends to bond to the hot kydex and start breaking down quickly. I use a layer of silicone rubber foam on top of my neoprene foam as a release layer and it has been holding up perfectly!
 
They make (or you can fudge your own) multiple cylinders end to end,
so the force is thru one rod.
 
A bit confused here..a different member name replied, are you using two screen names?

In regards to the press pictured through Alibaba, I would run screaming from that, pneumatics are not a exact science and those cylinder will not extend or retract in perfect time. The skinny little guide bars with take a dump in a heartbeat when things go sour, plus if you don't load both side of the press identically the cylinders will try to cant/tilt the press plate and again, things go sour. The picture looks cool but the engineering is..'fake news'!:eek:

Stuart

sorry yeah that's an old/personal account, didn't meean to do that. and thanks, that's great info, I really appreciate you looking out for me!

Why don't you just copy Aaron's press? If you're concerned that the plates will deflect, make them thicker.

Am working on it, would love to!

As the others have said I think a single cylinder with a larger diameter would be much easier and work better! My press generates less than 500# if I remember correctly so anything north of this should work fine for you! I don't think you'll need much pressure for the quench plates, and you definitely don't need a whole lot for thermoforming kydex as it's pretty pliable when it's hot. Too much pressure and you'll just crush the life out of your foam and reduce it's lifespan.

Also one tip: normal neoprene foams that are commonly used in kydex presses don't work so will in this application, because of the high clamp force it tends to bond to the hot kydex and start breaking down quickly. I use a layer of silicone rubber foam on top of my neoprene foam as a release layer and it has been holding up perfectly!

man great to see you here to help out Aaron! you're the man bro.

Did you get everything from mcmaster?

great tip on the silocone rubber roam... how come you don't use it in place of the neoprene foam? not moldable enough?
 
Did you get everything from mcmaster?

great tip on the silocone rubber roam... how come you don't use it in place of the neoprene foam? not moldable enough?

Yeah pretty much everything was from McMaster... The silicone rubber foam is much more expensive so I saved some money by just using a 1/2" layer of it. I don't think there would be any issue with using a thicker layer. I just went through my McMaster orders from the period around where I built the press, here are the part numbers for the various components:

Silicone foam: McMaster-Carr
Pneumatic cylinder: McMaster-Carr
Up/down switch: McMaster-Carr
Hand switches (x2): McMaster-Carr
Regulator: McMaster-Carr
Push to connect fittings: https://www.mcmaster.com/5779k283 - https://www.mcmaster.com/5779k109 - https://www.mcmaster.com/5779k151
 
In the original post you stated you wanted about 1000lbs of force. The 2 1/2" cylinder noted above, even at 120 PSI will only give you about 590lbs of force.

Stuart
 
Yeah pretty much everything was from McMaster... The silicone rubber foam is much more expensive so I saved some money by just using a 1/2" layer of it. I don't think there would be any issue with using a thicker layer. I just went through my McMaster orders from the period around where I built the press, here are the part numbers for the various components:

Silicone foam: McMaster-Carr
Pneumatic cylinder: McMaster-Carr
Up/down switch: McMaster-Carr
Hand switches (x2): McMaster-Carr
Regulator: McMaster-Carr
Push to connect fittings: https://www.mcmaster.com/5779k283 - https://www.mcmaster.com/5779k109 - https://www.mcmaster.com/5779k151

wow thanks so much for that!! HUGE help

In the original post you stated you wanted about 1000lbs of force. The 2 1/2" cylinder noted above, even at 120 PSI will only give you about 590lbs of force.

Stuart

So true! I'll see about getting the next step up. I'm honestly not sure how many lbs of force I need for quench plates... that may be enough.
 
Yeah pretty much everything was from McMaster... The silicone rubber foam is much more expensive so I saved some money by just using a 1/2" layer of it. I don't think there would be any issue with using a thicker layer. I just went through my McMaster orders from the period around where I built the press, here are the part numbers for the various components:

Silicone foam: McMaster-Carr
Pneumatic cylinder: McMaster-Carr
Up/down switch: McMaster-Carr
Hand switches (x2): McMaster-Carr
Regulator: McMaster-Carr
Push to connect fittings: https://www.mcmaster.com/5779k283 - https://www.mcmaster.com/5779k109 - https://www.mcmaster.com/5779k151

Question... how come you went w/ 2 hand switches vs only one? Will one work?
 








 
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